Integral tubing and/or electrical lead support and mounting pad for gas turbine engine controls and accessories

ABSTRACT

A new tubing (or electrical lead) support is combined with a new gas turbine engine control and accessory mounting pad, which also serves to communicate fluids/electrical signals to such controls and accessories to provide a more compact and easily maintained gas turbine engine. Tubing is permanently or semi-permanently bonded to the engine casing and the tubing is terminated in a shear face pad which provides &#39;&#39;&#39;&#39;plug in&#39;&#39;&#39;&#39; mounting pads for the controls and accessories.

[ 1 Jan. 16,1973

United States Patent 1 Rice 0.] 1 O3 3 m9 4 mm S B um N m I T m I A m mmL m mm P m l P. n m A .m Q R m o m LB W G T g m e 99 9 HM N H 200 G 5 Hon m x F 49 .l m w 33 E mm m T R w 0 DP N NU A R DOw m R U L T S LPNE TAI L C G O R A M N C O I R T mE E GC ML NC IEMEA [75] Inventor: Joe R.Rice, Cincinnati, Ohio primary Examiner Douglas Hart [73] Assignee:General Electric Company Assistant Examiner warren Olsen [22] Filed:Aug. 12, 1971 [21] Appl. No.: 171,065

Attorney-Derek P. Lawrence et a].

ABSTRACT A new tubing (or electrical lead) support is combined [52] U S60/3931 R 137/608 339/119 R with a new gas turbine engine control andaccessory mounting pad, which also serves to communicate [51] Int. 7/20.60/39.31, 39.32; 137/608;

fluids/electrical signals to such controls and accesso- [58] Field ofSearch ries to provide a more compact and easily maintained gas turbineengine. Tubing is permanently or semi-permanently bonded to the enginecasing and the tubing is terminated in a shear face pad which providesplug in mounting pads for the controls and accessories.

R w w 3 3 S T N m M A s w m n A mT S e R w W N U m w 2,978,869 4/1961Hiscock et al..... .................60/39.3l 14 Claims, 9 DrawingFigures PATENTEDJAH 16 I975 SHEET 1 [1F 2 OOOOOO INVENT OR. Jflf 6 F/(fPAIENTEUJAM 16 I975 SHEET 2 BF 2 INVENTOR. J05 5. 5/65 INTEGRAL TUBINGAND/OR ELECTRICAL LEAD SUPPORT AND MOUNTING PAD FOR GAS TURBINE ENGINECONTROLS AND ACCESSORIES BACKGROUND OF THE INVENTION This inventionrelates generally to tube and electrical lead supports and, moreparticularly, to a combined electrical lead and tubing support whichalso provides a lo mounting pad for control and accessory components ofa gas turbine engine. The invention herein described was made in thecourse of or under a contract or a subcontract thereunder, with theUnited States Departmentof the Air Force.

Advanced turbojet and turbofan engine designs for aircraft propulsionare becoming increasingly complex with regard to control and accessorymounting and location. Advanced designs require an increasingly largenumber of engine controls and accessories (hereafter normally referredto as controls), such as gearboxes, main and, possibly, augmenter fuelcontrols, hydraulic nozzle actuators, electronic temperature andpressure sensors, and the like. Most, if not all, of these controls aremounted externally of the gas turbine engine. That is, the controls arenormally mounted to a casing which surrounds the gas turbine engine.

Associated with these controls in an enormous amount of tubing fortransmitting fluid media and electrical cabling. For example, tubing isrequired to transmit fuel from the fuel tanks to a fuel control and fromthe fuel control to the fuel injection points of the engine. As anotherexample, tubes are required to deliver lubricating oil from an oil tankto any location on the engine which requires lubrication. Further,hydraulic oil tubes are required to deliver hydraulic fluid from asuitable source to hydraulic control mechanisms, such as hydraulicnozzle actuators which vary the exhaust area of the engine. Finally,electrical cabling is required to provide control signals for theabove-mentioned, and

many other components of the engine. As is the case 1 with the controlsthemselves, all of this tubing and cabling is also mounted externally ofthe gas turbine engine.

The size of an aircraft gas turbine engine is dictated by the airframeinstallation envelope, which normally imposes severe space limitationson the gas turbine designer. In addition, weapon system availability, orin the case of commercial aircraft, utilization factors, are determinedby the ease of maintenance and the resultant maintainability index(maintenance man hours per engine flight hour). Unfortunately, each ofthe various engine controls normally has associated with it a greatnumber of these tubes and electrical cables, which normally surround, orprotrude from the controls and connect to various locations on thecontrol. This not only increases the envelope size of the engine butalso requires the removal of each and every tubing connection andelectrical cable connection before the control or accessory can beremoved from the engine.

SUMMARY OF THE INVENTION It is an object of this invention, therefore,to provide a combined tubing/lead support and control mounting pad,which also provides for communication of fluids and electrical signalsto such controls and which reduces the envelope size of a gas turbineengine while permitting quick and easy removal of such engine controls.

Briefly stated, the above and other related objects are achieved byadopting a printed circuit concept for tubing and electrical leadswherein such tubing and leads are permanently or semi-permanentlyattached to or made an integral part of the gas turbine engineduct/casing and provided at their termination points with plug inmounting pads for engine controls. In one embodiment, the tubes andleads are routed through a honeycomb duct/casing structure withintroughs machined in the honeycomb, with the tubes/leads being bonded tothe duct and to each other with an epoxy filler. A fiberglass overlay orother appropriate cover is then used as in normal honeycomb ductmanufacture. The tubes and/or leads terminate in a shear face pad whichcan be utilized not only to communicate fluid and/or electrical signalsto a control but also to serve as a mounting flange face for thecontrol.

DESCRIPTION OF THE DRAWINGS While the specification concludes with aseries of claims which distinctly claim and particularly point out thesubject matter which applicant regards as his invention, anunderstanding of the invention will be gained from the followingdetailed description. This description is given in connection with theattached drawings, in which:

FIG. 1 is a schematic view, with portions deleted, of a gas turbineengine incorporating the subject invention;

FIG. 2 is a schematic end view of the gas turbine engine ofFIG. 1;

FIG. 3 is a plan view ofa portion of the bottom of the engine of FIG. 1;

FIG. 4 is an enlarged perspective view, with portions removed, of amounting system incorporating the present invention;

FIG. 5 is a partial sectional view, with portions removed, taken alongline 5--5 of FIG. 3;

FIGS. 6, 7, and 8 are partial sectional views showing alternativemethods of mounting tubing; and

FIG. 9 is a view similar to FIG. 4, showing an alternative mountingsystem.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawings whereinlike numerals correspond to like elements throughout, attention isdirected initially to FIG. 1 wherein a turbofan gas turbine engine 10 isshown schematically to include an outer casing 12 and a concentric innercasing 14 forming a fan duct 15 therebetween. A core engine is disposedwithin the casing 14 and comprises a rotor having at one end acompressor 16, which forms a converging annular passage 18 and at theother end a turbine 20. The engine further comprises a second rotorhaving at one end a low pressure compressor or fan 24 and at itsopposite end a fan turbine 26 which drives the fan 24. In highlysimplified terms, operation of this engine involves compression of anannular air stream by the compressor 16 in the passage 18. Ignition offuel in a combustor 28 generates a high energy gas stream which firstpasses through the turbine 20 to drive the core engine compressor 16 andthen passes through the fan turbine 26 to drive the fan 24.

Air entering the engine inlet, generally indicated at 30, is initiallycompressed by the fan 24. A portion of this compressed air enters thecore engine to generate the hot gas stream as described above. Theremaining portion of compressed air passes through the fan duct 15. Thehot gas stream leaving the combustors 28 first performs work on theturbine 20 to drive the compressor l6 and then performs work on the lowpressure turbine 26 to drive the fan 24. The hot gas stream then mixeswith the air stream exiting from the fan duct 15 and is dischargedthrough an exhaust nozzle 32 to provide a propulsive force.

To provide a desired propulsive force consistent with other operatingparameters, the exhaust nozzle 32 is of the variable area type andcomprises a plurality of leaves or fingers which are mechanicallyinterconnected as indicated by the broken line 34 to an actuation ring36. The actuation ring 36 is longitudinally shifted, relative to thecasing 12, by a plurality of system-type actuators 38 (only one of whichis shown) to increase or decrease the exit area of the nozzle 32. Thestructure described to this point is conventional and is well-known tothose skilled in the art.

In order to obtain a greater propulsive force, it is also known to burnadditional fuel either in the hot gas stream or in the fan duct airstream, or after a mixing of the two streams, prior to its exitingthrough the exhaust nozzle 32. This is generally referred to asaugmented or afterburner operation. In the present embodiment, combustormeans in the form of afterburner fuel nozzles 40 are provided in an areadownstream of the fan duct 15 to direct fuel to the mixture of gasleaving the fan duct 15 in the low pressure turbine 26.

In order to control the propulsive output (thrust) of the engine 10, itis necessary that the engine be provided with a number of basic controlsand accessories. For example, the amount of fuel delivered to both thecombustors 28 and the afterburner nozzles 40 must be closely controlled.For this reason, the engine 10 is provided with a main fuel control,shown schematically at 42, and an augmenter fuel control, shown at 44.The main fuel control 42 and the augmenter fuel control 44 operate todeliver fuel to the respective combustion systems by means of fuel pumps46 and 48, respectively. The main fuel pump 46 and the augmenter fuelpump 48 are each supplied with fuel from a suitable source (not shown)by means of tubing 50 and 52 (FIG. 3).

ln a normal installation, the main fuel pump 46 and the augmenter fuelpump 48 deliver fuel to their respective combustion systems as afunction of Mach number and/or engine speed. In order to provide anindication of the Mach number, the gas turbine engine 10 may be providedwith an inlet pressure tap 54, a fan stream static pressure tap 56, anda fan stream dynamic pressure tap 58. The output of each of thesepressure taps is normally connected to the fuel controls 42 and 44 bymeans of suitable tubing, e.g., tubes 60, 62, and 64, as shown in FIG.3.

In addition to the fuel controls discussed above, the propulsive outputof the engine 10 is further controlled by means of the variable areaexhaust nozzle 32. The actual area of the nozzle 32 is set by means of anozzle area control 66, which controls the actuators 38 in a well-knownmanner. The nozzle area control 66 normally has both fluid andelectrical inputs as shown schematically by lines 68 and 70 and controlsthe amount of hydraulic fluid delivered to the actuators 38 throughhydraulic lines 72 and 74.

While the above description is typical of many gas turbine engines,those skilled in the art will be readily aware of the fact that only afew of the many controls and accessories associated with a typical gasturbine engine have been described. The above description is givensolely to place the present invention in perspective in that the presentinvention includes a new tubing (or electrical lead) support combinedwith a new component mounting pad and fluid/electrical signalcommunicating device for the many controls, such as those describedabove, associated with a gas turbine engine. With this in mind,attention is now directed to FIG. 4 wherein a tubing and electrical leadlayout constructed in accordance with the present invention is shown.The layout is depicted for two typical controls, which are designated bythe numeral 76. The controls 76 are interconnected by means of aplurality of tubes 80. While four of the tubes 80 are shown, the numberof such tubes will vary greatly depending upon the particular control.Furthermore, it should be readily apparent that the tubes 80 may be usedfor the transmission of fluids, such as fuel, oil, hydraulic oil, etc.,or may be used as conduits for electrical leads.

As further shown in FIG. 4, the tubes 80 are positioned within aU-shaped trough 82 formed by a pair of leg members 84 and 86 whichextend from the engine casing 12. The tubes 80 may be positioned withinthe trough 82 either singularly, side-by-side, multiplestack, or in anyother arrangement. The tubes are then bonded to the engine casing 12and/or to each other with an epoxy filler, as indicated by the numeral88. A fiberglass overlay 90, or other appropriate cover, may then bepositioned over the epoxy filler 88, if necessary. While they are notshown, embedded clamps may be used as a normal practice or optionally tofurther assure retention of the tubes 80 within the trough 82.

As further shown in FIG. 4, the tubes 80 terminate in a shear pad 92which serves not only as a fluid/electrical signal communicating devicefor the control 76 but also serves as a mounting pad for the control 76.For this reason, the shear pad 92 includes a first flat side 94 fromwhich the tubes 80 extend and a flat surface 96, which serves as amounting pad for the control 76. While shown to be a flat plate, thesurface 96 could be manufactured to any configuration to accept a matingsurface of the control 76.

As further shown in FIG. 4, the shear pad 92 is connected to enginecasing 12 by means of a connecting rod 98. One end of the connecting rod98 is attached to an arm 100 which extends from the shear pad 92 bymeans of any suitable connectors, such as bolts 102. The opposite end ofthe connecting rod 98 is connected to a boss 104 which extends from thecasing 12 by means of a bolt 106. With such a mounting system, eitherend of the connecting rod 98 may be left free to rotate therebypermitting slight misalignment and/or movement of the shear pad 92.

In the embodiment shown in FIG. 4, the opposite end of the shear pad 92is not mounted directly to the casing 12, but instead is mounted to thecasing 12 indirectly through a connecting rod 108 which is attacheddirectly to the control 76.

In many cases it may be desirable, or necessary, to rigidly connect theshear pad 92 to the casing 12. One such design is shown in FIG. 5wherein the shear pad 92 is attached to a boss 110 extending from thecasing 12 by means of one or more bolts 112. As further shown in FIG. 5,the shear pad 92 includes a plurality of openings 114 in the mountingface 96 for communicating fluid (electrical signals) to passageways 116located internally of the controls 76. Furthermore, the mounting face 96includes one or more openings 188, which receive suitable connectorssuch as bolts 120, which attach the controls 76 to the shear pad 92.

Referring back to FIG. 4, the opposite ends of the tubes 80 from thosewhich terminate in the shear pad 92 are shown to terminate in a secondtype of shear pad 122 which does not serve as the sole mounting pad forthe control 76. In this embodiment, the control 76 would be mounteddirectly to the engine casing 12 in any suitable manner, while the tubes80 are connected to the control 76 through the shear pad 122. For thisreason, the shear pad 122 is rigidly connected to a mounting pad 124,which forms a portion of the control 76, by means of bolts 126. Whilethe shear pad 122 does not serve the dual functions of the shear pad 92,the shear pad 122 does cut down on maintenance in that all fluid andelectrical connections to the control 76 are made and broken through theshear pad 122. Thus, removal of the bolts 126 is all that is necessaryto break all of the fluid and electrical connections to the control 76.While the use of the shear pad 122 may be dictated by certain designconstraints, the use of the shear pad 92 is more desirable in that thistype of construction not only eliminates the need for individualconnectors protruding up from the casing surface 12, which in itselfcuts down on maintenance handling damage, but also eliminates the needfor separate mounting brackets for the controls and accessories.

While a number of possible embodiments of the present inventive concepthave been described in connection with FIGS. 4 and 5, those skilled inthe art will readily recognize other types of attachment methods whichwould fit within this broad inventive concept. For example, instead ofequipping the casing 12 with the trough 82, at least a portion of thecasing 12 could be made, as shown in FIG. 6, to include a structuralskin portion 128 which is surrounded by a honeycomb structure 130.Troughs 132 are machined within the honeycomb structure 130 at anylocation wherein tubing/electrical leads must be routed. The tubes 80 orelectrical leads 80' are positioned within the troughs 132 in anydesired arrangement. The tubes are then bonded to the structural skinportion 128 and/or to each other with an epoxy filler, as indicated bythe numeral 134. A fiberglass overlay 136, or other appropriate cover,may then be positioned on top of the honeycomb structure 130 as innormal honeycomb duct manufacture. Embedded clamps may be used as anormal practice or optionally to further assure retention of the tubeswithin the troughs 132.

As shown in FIG. 7, instead of machining or constructing a trough withinthe honeycomb structure 130, the tubes/leads could be placed on theouter surface of the casing 12 and either singularly or multiply fixedto the casing 12 by use of an epoxy or a fiberglass overlay 138. Hereagain, embedded clamps could be used to assure retention of tubes orleads, if necessary. Such tubes and leads would again terminate in shearpads similar to those described in connection with FIGS. 4 and 5.

In cases where it may be desirable or necessary to remove the tubing orelectrical leads, another alternative method of attachment, as shown inFIG. 8, may be used. This method is similar to that described inconnection with FIG. 7 in that the tubing or electrical leads arepositioned against the outer surface of the casing 12. A flexible cover140 is then provided around the tubing and connected to the casing 12 inany suitable manner. The cover 140 may be provided with an opening orslot 141 at any suitable location for the removal of the tubes orelectrical leads.

One further aspect of the present invention is that the shear pads 92and 122, described in connection with FIGS. 4 and 5, may also beprovided in connection with tubes and/or electrical leads which are notpermanently attached to the casing 12. That is, as shown in FIG. 9, thetubing may be connected to the casing 12 by means of suitable brackets142, a portion of which may be integrally formed with the casing 12 orconnected thereto in any known manner. At the location of each enginecontrol or accessory, the tubing 80 would terminate in a shear face pad144 which would again provide a mounting flange face 146 for suchcontrols or accessories. This type of construction would provide many ofthe advantages of the construction shown in connection with FIGS. 4 and5 and would provide the further advantage of being able to repositionthe engine controls and accessories during the early phases of an enginedesign. Once the position of the controls is frozen in the enginedesign, the tubing could then permanently be attached to the casing 12,if desired.

What I claim is:

1. In a gas turbine engine of the type including a casing defining aninternal flow path, a compressor, a combustion system, a turbine fordriving the compressor, and a plurality of casing-mounted controls forregulating the operation of said engine, the improvement comprising:

a combination mounting pad and fluid/electrical signal communicatingdevice for one of said engine controls, said device including a firstface for receiving a mating face of the control and a second face havingone or more tubes extending therefrom, said first face including one ormore openings which cooperate with said tubes to com municatefluid/electrical signals to the mounted control.

2. The improved mounting pad recited in claim 1 further characterized inthat said first face includes a second set of openings for receivingmeans for rigidly connecting the control to said first face.

3. The improved mounting pad recited in claim 2 further including meansfor connecting said device to the engine casing.

4. The improved mounting pad recited in claim 2 in combination withmeans for permanently connecting said tubes to the engine casing.

5. The combination recited in claim 4 wherein said tube connecting meansincludes a trough formed on the exterior of said casing for receivingsaid tubes.

6. The combination recited in claim wherein said tubes are positionedwithin said trough and are bonded to said casing by means of an epoxyfiller.

7. The combination recited in claim 4 wherein said tubes are connectedto said casing by means of an epoxy cement.

8. The combination recited in claim 4 wherein said tubes are connectedto said casing by means of a flexible cover which surrounds said tubesand which is attached to said casing.

9. The combination recited in claim 8 wherein said flexible coverincludes an opening for removal of said tubes.

10. In a gas turbine engine with an exterior casing a mounting pad for agas turbine engine control comprising a first face for receiving amating face of said control, said first face including means forconnecting the control thereto, a second face extending generallyperpendicular to said first face and having one or more fluidcommunicating tubes extending therefrom, and means for connecting saidmounting pad to the exterior casing of the engine.

11. The mounting pad recited in claim 10 wherein said means forconnecting said pad to the casing provide a rigid connection.

12. The mounting pad recited in claim 11 wherein said connecting meansinclude one or more bosses extending from said casing for receivingbolts which attach said mounting pad to said casing.

13. The mounting pad recited in claim 10 wherein said connecting meansprovide a flexible mount whereby slight movement of said pad withrespect to said casing is possible.

14. The mounting pad recited in claim 13 wherein said connecting meansincludes one or more connecting rods extending from and connected to apivot point formed on said casing.

1. In a gas turbine engine of the type including a casing defining aninternal flow path, a compressor, a combustion system, a turbine fordriving the compressor, and a plurality of casing-mounted controls forregulating the operation of said engine, the improvement comprising: acombination mounting pad and fluid/electrical signal communicatingdevice for one of said engine controls, said device including a firstface for receiving a mating face of the control and a second face havingone or more tubes extending therefrom, said first face including one ormore openings which cooperate with said tubes to communicatefluid/electrical signals to the mounted control.
 2. The improvedmounting pad recited in claim 1 further characterized in that said firstface includes a second set of openings for receiving means for rigidlyconnecting the control to said first face.
 3. The improved mounting padrecited in claim 2 further including means for connecting said device tothe engine casing.
 4. The improved mounting pad recited in claim 2 incombination with means for permanently connecting said tubes to theengine casing.
 5. The combination recited in claim 4 wherein said tubeconnecting means includes a trough formed on the exterior of said casingfor receiving said tubes.
 6. The combination recited in claim 5 whereinsaid tubes are positioned within said trough and are bonded to saidcasing by means of an epoxy filler.
 7. The combination recited in claim4 wherein said tubes are connected to said casing by means of an epoxycement.
 8. The combination recited in claim 4 wherein said tubes areconnected to said casing by means of a flexible cover which surroundssaid tubes and which is attached to said casing.
 9. The combinationrecited in claim 8 wherein said flexible cover includes an opening forremoval of said tubes.
 10. In a gas turbine engine with an exteriorcasing a mounting pad for a gas turbine engine control comprising afirst face for receiving a mating face of said control, said first faceincluding means for connecting the control thereto, a second faceextending generally perpendicular to said first face and having one ormore fluid communicating tubes extending therefrom, and means forconnecting said mounting pad to the exterior casing of the engine. 11.The mounting pad recited in claim 10 wherein said means for connectingsaid pad to the casing provide a rigid connection.
 12. The mounting padrecited in claim 11 wherein said connecting means include one or morebosses extending from said casing for receiving bolts which attach saidmounting pad to said casing.
 13. The mounting pad recited in claim 10wherein said connecting means provide a flexible mount whereby slightmovement of said pad with respect to said casing is possible.
 14. Themounting pad recited in claim 13 wherein said connecting means includesone or more connecting rods extending from and connected to a pivotpoint formed on said casing.